Isolation for carrier aggregation circuit

ABSTRACT

Improved isolation for carrier aggregation circuit. In some embodiments, a carrier aggregation circuit can include a common input node and a common output node, and a multiplexer configured to support first and second bands. The carrier aggregation circuit can further include a first path implemented between the common input node and the common output node, and be configured to support the first band, with the first path including a pre-multiplexer switch, the multiplexer, a first post-multiplexer switch, and a first enable switch. The carrier aggregation circuit can further include a second path implemented between the common input node and the common output node, and be configured to support the second band, with the second path including the pre-multiplexer switch, the multiplexer, a second post-multiplexer switch, and a second enable switch different than the first enable switch.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. application Ser. No.14/683,539 filed Apr. 10, 2015, entitled ARCHITECTURES AND METHODSRELATED TO IMPROVED ISOLATION FOR DIPLEXER PATHS, which claims priorityto and the benefit of the filing date of U.S. Provisional ApplicationNo. 61/978,879 filed Apr. 12, 2014, entitled ARCHITECTURES AND METHODSRELATED TO IMPROVED ISOLATION FOR DIPLEXER PATHS, the benefits of thefiling dates of which are hereby claimed and the disclosures of whichare hereby expressly incorporated by reference herein in their entirety.

BACKGROUND Field

The present disclosure relates to diplexer paths having improvedisolation.

Description of the Related Art

Semiconductor switches are commonly used for radio-frequency (RF)applications. Such switches can be combined with conductive paths toform RF circuits. A switch can be turned ON (closed) or OFF (opened) byapplication of appropriate switching signal(s).

SUMMARY

According to some teachings, the present disclosure relates to anarchitecture for routing radio-frequency (RF) signals. The architectureincludes an input node and an output node, and a distributed network ofsignal paths implemented between the input node and the output node. Thedistributed network of signal paths includes a first path having Nswitches including a selected switch, with the quantity N being aninteger greater than 2. The first path is capable of routing a first RFsignal between the input node and the output node when enabled. Thedistributed network of signal paths further includes a second pathcapable of routing a second RF signal between the input node and theoutput node. The second path includes the selected switch. The secondpath includes a plurality of open switches when disabled and the firstpath is enabled.

In some embodiments, the input node can include a node coupled to anantenna port. The output node can include a node coupled to an input ofa low-noise amplifier (LNA).

In some embodiments, the distributed network of signal paths can includea plurality of multiplexers, with each multiplexer including a pluralityof ports multiplexed unto a common port. Each multiplexer can be adiplexer. The distributed network of signal paths can include aplurality of diplexer selection paths between the input node andrespective common ports of the diplexers, with each diplexer selectionpath including a diplexer selection switch.

In some embodiments, the distributed network of signal paths can furtherinclude a first port selection path and a second port selection path foreach diplexer. Each of the first port selection path and the second portselection path can include a port selection switch. The distributednetwork of signal paths can further include an enable selection paththat couples a plurality of the port selection paths to the output node.Each of the enable selection path can include an enable switch.

In some embodiments, the selected switch can be one of the diplexerselection switches. In some embodiments, the first port selection pathand the second port selection path for a given diplexer can be coupledto two different enable selection paths. In some embodiments, each pathin the distributed network of signal paths can include a correspondingenable selection path, a corresponding port selection port, and acorresponding diplexer selection path, such that the quantity N is 3.The second path can include two open switches when disabled and thefirst path is enabled. The two open switches can be the port selectionswitch and the enable switch corresponding to the second path.

In some embodiments, at least some of the distributed network of signalpaths can be configured to be capable of operating in a carrieraggregation (CA) mode. In some embodiments, the distributed network ofsignal paths can be configured to be operated in a non-carrieraggregation mode.

In some embodiments, the disabled second path with the plurality of openswitches can provide improved isolation performance for the second paththan a disabled signal path having one open switch.

In some implementations, the present disclosure relates to aradio-frequency (RF) module that includes a packaging substrateconfigured to receive a plurality of components, and an input node andan output node implemented on or within the packaging substrate. The RFmodule further includes a plurality of signal conditioning circuitsimplemented on or within the packaging substrate. The RF module furtherincludes a distributed network of signal paths configured to route RFsignals to and from the plurality of signal conditioning circuitsbetween the input node and the output node. The distributed network ofsignal paths includes a first path having N switches including aselected switch, with the quantity N being an integer greater than 2.The first path is capable of routing a first RF signal between the inputnode and the output node when enabled. The distributed network of signalpaths further includes a second path capable of routing a second RFsignal between the input node and the output node. The second pathincludes the selected switch. The second path includes a plurality ofopen switches when disabled and the first path is enabled.

In some embodiment, the plurality of signal conditioning circuits caninclude a plurality of diplexers. In some embodiment, the RF module canfurther include a low-noise amplifier (LNA) implemented on the packagingsubstrate. The LNA can be coupled to the output node to receive thefirst RF signal through the first path when the first path is enabled.

In some embodiment, the RF module can be a front-end module. In someembodiment, the RF module can be a diversity receive (DRx) module. Insome embodiment, the LNA can be implemented on a first semiconductordie. In some embodiment, some or all of the switches associated with thedistributed network of signal paths can be implemented on a secondsemiconductor die.

In a number of implementations, the present disclosure relates to amethod for fabricating a radio-frequency (RF) module. The methodincludes providing or forming a packaging substrate configured toreceive a plurality of components. The method further includesimplementing a plurality of signal conditioning circuits on or withinthe packaging substrate between an input node and an output node. Themethod further includes forming a distributed network of signal paths toroute RF signals to and from the plurality of signal conditioningcircuits between the input node and the output node. The distributednetwork of signal paths includes a first path having N switchesincluding a selected switch, with the quantity N being an integergreater than 2. The first path is capable of routing a first RF signalbetween the input node and the output node when enabled. The distributednetwork of signal paths further includes a second path capable ofrouting a second RF signal between the input node and the output node.The second path includes the selected switch. The second path includes aplurality of open switches when disabled and the first path is enabled.

In accordance with a number of implementations, the present disclosurerelates to a radio-frequency (RF) device that includes a receiverconfigured to process RF signals, and a front-end module (FEM) incommunication with the receiver. The FEM includes a plurality of signalconditioning circuits, and a distributed network of signal pathsconfigured to route the RF signals to and from the plurality of signalconditioning circuits between an input node and an output node. Thedistributed network of signal paths includes a first path having Nswitches including a selected switch, with the quantity N being aninteger greater than 2. The first path is capable of routing a first RFsignal between the input node and the output node when enabled. Thedistributed network of signal paths further includes a second pathcapable of routing a second RF signal between the input node and theoutput node. The second path includes the selected switch. The secondpath includes a plurality of open switches when disabled and the firstpath is enabled. The RF device further includes an antenna incommunication with the input node, with the antenna being configured toreceive the RF signals.

In some embodiments, the RF device can include a wireless device. Thewireless device can be, for example, a cellular phone. In someembodiments, the antenna can include a diversity antenna, and the RFmodule can include a diversity receive (DRx) module). The wirelessdevice can further include an antenna switch module (ASM) configured toroute the RF signals from the diversity antenna to the receiver. The DRxmodule can be implemented between the diversity antenna and the ASM.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the inventions have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment of the invention.Thus, the invention may be embodied or carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other advantages as may be taughtor suggested herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of an assembly of radio-frequency (RF)signal paths having improved isolation performance.

FIG. 2 shows a more specific example of the assembly of RF signal pathsof FIG. 1.

FIGS. 3A and 3B show different paths that can be implemented in anexample configuration of band-selection paths involving a plurality ofdiplexers.

FIG. 4 shows spectrum responses for the four example enabled paths ofFIGS. 3A and 3B.

FIG. 5 shows an example of a distributed network of RF signal paths thatcan provide improved isolation for at least some of the disabled paths.

FIG. 6 shows another example of a distributed network of RF signal pathsthat can provide improved isolation for at least some of the disabledpaths.

FIGS. 7A-7D show four signal paths that can be enabled for the exampleconfiguration of FIG. 5.

FIG. 8 shows that in some embodiments, a distributed network of signalpaths having one or more features as described herein can include shuntpaths to facilitate isolation associated with some or all of the signalpaths.

FIG. 9 shows examples of transmitted power spectra for the fourdifferent enabled paths of the examples of FIGS. 5 and 6.

FIG. 10 shows that in some embodiments, a distributed network of signalpaths can be implemented with more than two diplexers.

FIG. 11 shows that in some embodiments, a distributed network of signalpaths between two common nodes does not necessarily need to have all ofthe paths configured with enhanced isolation as described herein.

FIG. 12 shows a process that can be implemented to fabricate a devicesuch as a module having one or more features as described herein.

FIG. 13 shows that one or more features of the present disclosure can beimplemented in an RF module.

FIG. 14 shows an example wireless device having one or more features asdescribed herein.

FIG. 15 shows that one or more features of the present disclosure can beimplemented in a diversity receive module.

FIG. 16 shows an example wireless device having the diversity receivemodule of FIG. 15.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The headings provided herein, if any, are for convenience only and donot necessarily affect the scope or meaning of the claimed invention.

Semiconductor switches are used frequently in integrated circuits,including those configured for processing radio-frequency (RF) signals.Such switches can be combined with conductive paths to form and/orfacilitate various RF circuits. A switch can be turned ON (closed) orOFF (opened) by application of appropriate switching signal(s), and sucha switch can include one or more semiconductor devices (such asfield-effect transistors (FETs) and related devices) arranged to allow(when ON) or inhibit (when OFF) passage of RF signals. Accordingly, aswitch in its OFF state provides more isolation between its twoterminals than when in the ON state.

Disclosed herein are examples of how switchable paths can be arranged toallow routing of various RF signals in a selected manner while providingimproved isolation for paths that are turned OFF. For the purpose ofdescription herein, a switch can include a semiconductor switchingdevice based on, for example, one or more FETs, MOSFET, SOI-MOSFET, etc.It will be understood that one or more features of the presentdisclosure can also be implemented with other types of switchingdevices.

FIG. 1 shows a block diagram of an assembly of radio-frequency (RF)signal paths (100) having improved isolation performance. Such anassembly of signal paths can be configured to receive an RF signalthrough a common input 102 (IN), process the RF signal along one or moreof a plurality of paths, and yield a processed RF signal through acommon output 104 (OUT).

FIG. 2 shows a more specific example of the assembly of RF signal paths100 of FIG. 1. In FIG. 2, a band selection architecture 110 can beimplemented for a receiver circuit that includes a low-noise amplifier(LNA) 120. Such an LNA can receive an RF signal that has beenband-selected and processed through an assembly of band-selection paths100. Such an assembly of band-selection paths can be configured toreceive an input signal (RF_IN) through an input node 102. Such an inputsignal can be received through, for example, a common antenna (notshown), and can include one or more cellular band specific frequencycomponents. As described herein, the assembly of band-selection paths100 can include filters (e.g., band-pass filters) that pass filtered RFsignals having selected band content(s) to an output node 104. Such anoutput node can be coupled to an input of the LNA 120, so as to allowamplification of the selected-band RF signal. Such an amplified RFsignal (RF_OUT) is shown to be provided to an LNA output node 112.

FIGS. 3A and 3B show an example configuration of band-selection paths 10involving a plurality of diplexers. In the example configuration 10, anRF signal is shown to be received through an antenna port (ANT) anddistributed to a first diplexer through a first switched path (with aswitch S1), and a second diplexer through a second switched path (with aswitch S2). For the purpose of description of FIGS. 3A and 3B, theswitches S1 and S2 can be referred to as diplexer selection switches.

Each diplexer is shown to include two output paths, such that the twodiplexers collectively have four output ports coupled to theirrespective paths. Path 1 and Path 2 correspond to the two output portsof the first diplexer, and Path 3 and Path 4 correspond to the twooutput ports of the second diplexer.

Path 1 is shown to be switchable by a switch S3; Path 2 is shown to beswitchable by a switch S4; Path 3 is shown to be switchable by a switchS5; and Path 4 is shown to be switchable by a switch S6. For the purposeof description of FIGS. 3A and 3B, the switches S3-S6 can be referred toas diplexer output path selection switches, or as diplexer portselection switches.

The two paths (Path 1 and Path 2) corresponding to the first diplexerare shown to be combined, and the combined path is shown to beswitchable by an enable switch S7. Similarly, the two paths (Path 3 andPath 4) corresponding to the second diplexer are shown to be combined,and the combined path is shown to be switchable by an enable switch S8.The two combined paths corresponding to the switches S7 and S8 are shownto be further combined so as to yield a common output that leads to aninput of an LNA (not shown).

The example distributed network of switchable paths (10) in FIGS. 3A and3B allows the two paths (Path 1, Path 2) associated with the firstdiplexer to be enabled together by closing of the first enable switchS7. In such an enabled state, either of Path 1 and Path 2 can be enabledby closing one switch (S3 or S4) and opening the other switch (S4 orS3). Similarly, the two paths (Path 3, Path 4) associated with thesecond diplexer can be enabled together by closing of the second enableswitch S8; and in such an enabled state, either of Path 3 and Path 4 canbe enabled by closing one switch (S5 or S6) and opening the other switch(S6 or S5).

The foregoing example of selecting output path for a given diplexerassumes that the network of switchable paths is being operated in anon-carrier aggregation (non-CA) mode. In some embodiments, a givendiplexer and its corresponding output paths can be configured to operatein a CA mode. For example, the first diplexer can be operated in a CAmode by closing the first enable switch S7, and closing both of theswitches (S3, S4) corresponding to Path 1 and Path 2. In such a mode,the second enable switch S8 and both of the switches S5, S6 can beopened. Similarly, the second diplexer can be operated in a CA mode byclosing the second enable switch S8, and closing both of the switches(S5, S6) corresponding to Path 3 and Path 4. In such a mode, the firstenable switch S7 and both of the switches S3, S4 can be opened.

In the context of non-CA mode of operation, or in situations whereselection of a given output path from the diplexer is desired (whetheror not the configuration is CA capable), switching configurations aslisted in Table 1 can be implemented.

TABLE 1 Enabled path S1 S2 S3 S4 S5 S6 S7 S8 Path 1 ON OFF ON OFF OFFOFF ON OFF Path 2 ON OFF OFF ON OFF OFF ON OFF Path 3 OFF ON OFF OFF ONOFF OFF ON Path 4 OFF ON OFF OFF OFF ON OFF ONIn the example of FIG. 3A, Path 2 corresponding to the first diplexer isenabled by the switching configuration as shown and listed in Table 1 tothereby yield a signal path 12. In the example of FIG. 3B, Path 3corresponding to the second diplexer is enabled by the switchingconfiguration as shown and listed in Table 1 to thereby yield a signalpath 12.

In the example of FIG. 3A, the enabled Path 2 results in switches S1, S4and S7 being closed, and all other switches being opened. Accordingly,isolation between the ANT node and the LNA node includes one open switch(S3) through the disabled Path 1, three open switches (S2, S5, S8)through the disabled Path 3, and three open switches (S2, S6, S8)through the disabled Path 4.

Similarly, in the example of FIG. 3B, the enabled Path 3 results inswitches S2, S5 and S8 being closed, and all other switches beingopened. Accordingly, isolation between the ANT node and the LNA nodeincludes three open switches (S1, S3, S7) through the disabled Path 1,three open switches (S1, S4, S7) through the disabled Path 2, and oneopen switch (S6) through the disabled Path 4.

Based on the foregoing examples, one can see that whenever a given pathis enabled, at least one disabled path between the input node (ANT) andthe output node (LNA) has only one open switch. For example, enabling ofPath 2 in FIG. 3A results in the path which includes Path 1 to have onlyone switch (S3) open for the isolation of the band corresponding to Path1 between the ANT node and the LNA node. In another example, enabling ofPath 3 in FIG. 3B results in the path which includes Path 4 to have onlyone switch (S6) open for the isolation of the band corresponding to Path4 between the ANT node and the LNA node.

In FIGS. 3A and 3B, examples of bands that can be serviced by thediplexers are shown. The first diplexer can be configured to providediplexing functionality for example cellular bands B30 and B41b/38, andthe second diplexer can be configured to provide diplexing functionalityfor example cellular bands B40 and B41a. In the context of such examplebands, FIG. 4 shows spectrum responses for the four different enabledpaths as described in reference to Table 1. The upper left panel showspower spectra for the bands B30, B41b/38, B40 and B41a when the pathcorresponding to B30 (Path 1) is enabled, and the path for B41b/38 (Path2) has only one open switch (S4). The upper right panel shows powerspectra for the bands B30, B41b/38, B40 and B41a when the pathcorresponding to B41b (Path 2) is enabled, and the path for B30 (Path 1)has only one open switch (S3). The lower left panel shows power spectrafor the bands B30, B41b/38, B40 and B41a when the path corresponding toB40 (Path 3) is enabled, and the path for B41a (Path 4) has only oneopen switch (S6). The lower right panel shows power spectra for thebands B30, B41b/38, B40 and B41a when the path corresponding to B41a(Path 4) is enabled, and the path for B40 (Path 3) has only one openswitch (S5).

As shown in the upper left panel (B30 enabled, B41b/38 with only oneopen switch, each of B40 and B41a with three open switches), the gainfor B41b/38 (about −20 dB) is much greater than those for B40 and B41a.As shown in the lower left panel (B40 enabled, B41a with only one openswitch, each of B30 and B41b/38 with three open switches), gain forB41b/38 is reduced to about −34 dB which is a significant reduction fromthe −20 dB example of the upper left panel. The improvement in isolationof B41b/38 in the lower left panel is at least in part due to the threeopen switches compared to only one open switch in the upper left panel.

Similarly, in the upper right panel (B41b/38 enabled, B30 with only oneopen switch, each of B40 and B41a with three open switches), the gainfor B30 (about −28 dB) is much greater than those for B40 and B41a. Asshown in the lower left panel (B40 enabled, B41a with only one openswitch, each of B30 and B41b/38 with three open switches), gain for B30is reduced to about −38 dB which is a significant reduction from the −28dB example of the upper right panel. The improvement in isolation of B30in the lower left panel is at least in part due to the three openswitches compared to only one open switch in the upper right panel.

FIGS. 5 and 6 show examples of distributed networks of RF signal paths100 that can provide improved isolation for one or more disabled pathsthan the example of FIGS. 3A and 3B. In FIGS. 5 and 6, the same switchesS1-S8 as in FIGS. 3A and 3B can be utilized to provide variousswitchable signal paths through two example diplexers 130, 132. However,the examples of FIGS. 5 and 6 can have such signal paths configured sothat any disabled path between an antenna node (ANT) and an LNA node(LNA) includes at least two open switches (instead of only one openswitch in certain paths in FIGS. 3A and 3B). As described herein, suchan increase in the number of open switches provides improvements inisolation for the corresponding disabled paths. As also describedherein, such improvements in isolation for the disabled paths can beachieved utilizing the same overall number of switches.

In the example configurations 100 of FIGS. 5 and 6, an RF signal isshown to be received through an antenna port (ANT) and distributed to afirst diplexer 130 through a first switched path (with a switch S1), andto a second diplexer 132 through a second switched path (with a switchS2). For the purpose of description of FIGS. 5 and 6, the switches S1and S2 can be referred to as diplexer selection switches.

Each diplexer is shown to include two output ports, such that the twodiplexers collectively have four output ports coupled to theirrespective paths through respective switches. In the example of FIG. 5,Path 1 and Path 4 are coupled to the two output ports of the firstdiplexer 130 through switches S3 and S6, respectively, and Path 3 andPath 2 are coupled to the two output ports of the second diplexer 132through switches S5 and S4, respectively. In the example of FIG. 6, Path3 and Path 2 are coupled to the two output ports of the first diplexer130 through switches S5 and S4, respectively, and Path 1 and Path 4 arecoupled to the two output ports of the second diplexer 132 throughswitches S3 and S6, respectively.

In both of the examples of FIGS. 5 and 6, Path 1 is shown to beswitchable by a switch S3; Path 2 is shown to be switchable by a switchS4; Path 3 is shown to be switchable by a switch S5; and Path 4 is shownto be switchable by a switch S6. For the purpose of description of FIGS.5 and 6, the switches S3-S6 can be referred to as diplexer output pathselection switches, or diplexer port selection switches.

In the example of FIG. 5, Path 1 corresponding to the first diplexer 130and Path 2 corresponding to the second diplexer 132 are shown to becombined, and the combined path is shown to be switchable by an enableswitch S7. Similarly, Path 3 corresponding to the second diplexer 132and Path 4 corresponding to the first diplexer 130 are shown to becombined, and the combined path is shown to be switchable by an enableswitch S8. The two combined paths corresponding to the switches S7 andS8 are shown to be further combined so as to yield a common output thatleads to an input of an LNA (not shown).

In the example of FIG. 6, Path 1 corresponding to the second diplexer132 and Path 2 corresponding to the first diplexer 130 are shown to becombined, and the combined path is shown to be switchable by an enableswitch S7. Similarly, Path 3 corresponding to the first diplexer 130 andPath 4 corresponding to the second diplexer 132 are shown to becombined, and the combined path is shown to be switchable by an enableswitch S8. The two combined paths corresponding to the switches S7 andS8 are shown to be further combined so as to yield a common output thatleads to an input of an LNA (not shown).

The example distributed networks of switchable paths of FIGS. 5 and 6allow the two paths (Path 1, Path 2) associated with two differentdiplexers to be enabled together by closing of the first enable switchS7. In such an enabled state, either of Path 1 and Path 2 can be enabledby closing one switch (S3 or S4) and opening the other switch (S4 orS3). Similarly, the two paths (Path 3, Path 4) associated with twodifferent diplexers can be enabled together by closing of the secondenable switch S8; and in such an enabled state, either of Path 3 andPath 4 can be enabled by closing one switch (S5 or S6) and opening theother switch (S6 or S5).

The foregoing examples of selecting an output path for a given diplexerassumes that the network of switchable paths is being operated in anon-carrier aggregation (non-CA) mode. In some embodiments, a givendiplexer and its corresponding output paths can be configured to operatein a CA mode. For example, in FIG. 5, the first diplexer 130 can beoperated in a CA mode by closing both of the first and second enableswitches (S7, S8), and closing both of the switches (S3, S6)corresponding to Path 1 and Path 4. In such a mode, both of the firstand second diplexer selection switches (S1, S2) can be closed. Inanother example, in FIG. 6, the first diplexer 130 can be operated in aCA mode by closing both of the first and second enable switches (S7,S8), and closing both of the switches (S5, S4) corresponding to Path 3and Path 2. In such a mode, both of the first and second diplexerselection switches (S1, S2) can be closed.

In the context of non-CA mode of operation, or in situations whereselection of a given output path from the diplexer is desired (whetheror not the configuration is CA capable), switching configurations aslisted in Table 2 can be implemented for the example of FIG. 5, and aslisted in Table 3 for the example of FIG. 6.

TABLE 2 Enabled path S1 S2 S3 S4 S5 S6 S7 S8 Path 1 ON OFF ON OFF OFFOFF ON OFF Path 2 OFF ON OFF ON OFF OFF ON OFF Path 3 OFF ON OFF OFF ONOFF OFF ON Path 4 ON OFF OFF OFF OFF ON OFF ON

TABLE 3 Enabled path S1 S2 S3 S4 S5 S6 S7 S8 Path 1 OFF ON ON OFF OFFOFF ON OFF Path 2 ON OFF OFF ON OFF OFF ON OFF Path 3 ON OFF OFF OFF ONOFF OFF ON Path 4 OFF ON OFF OFF OFF ON OFF ON

FIGS. 7A-7D show four signal paths that can be enabled for the exampleconfiguration of FIG. 5. In the example of FIG. 7A, Path 1 correspondingto the first diplexer 130 is enabled by the switching configuration asshown and listed in Table 2 to thereby yield a signal path 140. In theexample of FIG. 7B, Path 2 corresponding to the second diplexer 132 isenabled by the switching configuration as shown and listed in Table 2 tothereby yield a signal path 142. In the example of FIG. 7C, Path 3corresponding to the second diplexer 132 is enabled by the switchingconfiguration as shown and listed in Table 2 to thereby yield a signalpath 144. In the example of FIG. 7D, Path 4 corresponding to the firstdiplexer 130 is enabled by the switching configuration as shown andlisted in Table 2 to thereby yield a signal path 146.

In the example of FIG. 7A, the enabled Path 1 results in switches S1, S3and S7 being closed, and all other switches being opened. Accordingly,isolation between the ANT node and the LNA node includes two openswitches (S2, S4) through the disabled Path 2, three open switches (S2,S5, S8) through the disabled Path 3, and two open switches (S6, S8)through the disabled Path 4.

Similarly, in the example of FIG. 7B, the enabled Path 2 results inswitches S2, S4 and S7 being closed, and all other switches beingopened. Accordingly, isolation between the ANT node and the LNA nodeincludes two open switches (S1, S3) through the disabled Path 1, twoopen switches (S5, S8) through the disabled Path 3, and three openswitches (S1, S6, S8) through the disabled Path 4.

Similarly, in the example of FIG. 7C, the enabled Path 3 results inswitches S2, S5 and S8 being closed, and all other switches beingopened. Accordingly, isolation between the ANT node and the LNA nodeincludes three open switches (S1, S3, S7) through the disabled Path 1,two open switches (S4, S7) through the disabled Path 2, and two openswitches (S1, S6) through the disabled Path 4.

Similarly, in the example of FIG. 7D, the enabled Path 4 results inswitches S1, S6 and S8 being closed, and all other switches beingopened. Accordingly, isolation between the ANT node and the LNA nodeincludes two open switches (S3, S7) through the disabled Path 1, threeopen switches (S2, S4, S7) through the disabled Path 2, and two openswitches (S2, S5) through the disabled Path 3.

Based on the foregoing examples related to FIGS. 7A-7D, one can see thatwhenever a given path is enabled, each of the disabled paths includes atleast two open switches between the input node (ANT) and the output node(LNA). Similar enabling of the four paths and the corresponding disabledpaths having at least two open switches can be implemented for theexample configuration of FIG. 6.

FIG. 8 shows that in some embodiments, a distributed network 100 ofsignal paths having one or more features as described herein can includeshunt paths to facilitate isolation associated with some or all of thesignal paths. The example shown in FIG. 8 is similar to the exampleconfiguration of FIG. 5. However, in FIG. 8, switchable shunt paths (148a, 148 b, 148 c, 148 d) to ground are shown to be provided along thediplexer paths, before their respective switches S3, S4, S5, S6.

In some embodiments, each of the shunt paths (148 a, 148 b, 148 c, 148d) can include a shunt switch, and such a shunt switch can be closed oropened when the switch along the corresponding diplexer output path isopened or closed. For example, when Path 1 is disabled, switch S3 isopened (along with switch S1); and in such a state, the shunt switch forthe shunt path 148 a can be closed so as to allow any residual signaland/or noise to be shunted to ground. When Path 1 is enabled, switch S3closed opened (along with switch S1); and in such a state, the shuntswitch for the shunt path 148 a can be opened. The shunt switches forthe shunt paths 148 b, 148 c, 148 d can be operated in a similar manner.

In FIGS. 5-8, examples of bands that can be serviced by the diplexersare shown. The first diplexer 130 can be configured to provide diplexingfunctionality for example cellular bands B30 and B41b/38, and the seconddiplexer 132 can be configured to provide diplexing functionality forexample cellular bands B40 and B41a. In the context of such examplebands, FIG. 9 shows transmitted power spectra for the four differentenabled paths as described in reference to Tables 2 and 3.

The upper left panel in FIG. 9 shows power spectra for the bands B30,B41b/38, B40 and B41a when the path corresponding to B30 (Path 1 in FIG.5, Path 3 in FIG. 6) is enabled, and the path for B41b/38 has two openswitches (S6, S8) in FIG. 5 and two open switches (S4, S7) in FIG. 6.The upper right panel shows power spectra for the bands B30, B41b/38,B40 and B41a when the path corresponding to B41b/38 (Path 4 in FIG. 5,Path 2 in FIG. 6) is enabled, and the path for B30 has two open switches(S3, S7) in FIG. 5 and two open switches (S5, S8) in FIG. 6. Similarly,the lower left panel shows power spectra for the bands B30, B41b/38, B40and B41a when the path corresponding to B40 is enabled. Similarly, thelower right panel shows power spectra for the bands B30, B41b/38, B40and B41a when the path corresponding to B41a is enabled.

In the examples described in reference to FIGS. 3 and 4, and moreparticularly in reference to the upper left panel of FIG. 4, B30 beingenabled results in the disabled path for B41b/38 having only one openswitch and yielding a relatively poor isolation at about −20 dB. In theupper left panel of FIG. 9 where B30 is enabled and the disabled pathfor B41b/38 includes two open switches, the isolation for B41b/38 isshown to be at a significantly improved level of about −31 dB. Comparedto the one-open-switch example of FIG. 4, the isolation provided by thetwo-open-switches example of FIG. 9 is improved by about 9 dB.

In the examples of FIGS. 5-8, improved isolation can be achieved byforming output paths of a given diplexer to two separate enableswitches. When there are only two diplexers, such a configurationessentially results in swapping of one output path of the first diplexerwith one output path of the second diplexer. When there are more thantwo diplexers, such swapping can be implemented between pair(s) ofdiplexers, among different diplexers, or some combination thereof.

For example, FIG. 10 shows a distributed network of signal paths 100that includes three signal conditioning circuits 150, 152, 154 such asdiplexers. Switches S1, S2, S3 are shown to couple the circuits 150,152, 154 to a common node 102. In the context of diplexers, the switchesS1, S2, S3 can be diplexer-selection switches. Switches S4, S5, S6, S7,S8, S9 are show to provide switchable paths coupled to the other sidesof the circuits 150, 152, 154. In the context of diplexers, the switchesS4, S5, S6, S7, S8, S9 can provide switchable output paths for the threediplexers. The switches S4, S5, S6, S7, S8, S9 are shown to be combinedin various pairs to form three combined paths. The three combined pathsare shown to provide switchable paths to a common node 104 throughswitches S10, S11, S12. In the context of diplexers, the switches S10,S11, S12 can be enable switches.

As with the various examples of FIGS. 5-8, disabled signal paths betweenthe node 102 and the node 104 of FIG. 10 can benefit from having atleast two open switches. In FIG. 10, however, the example configuration100 shows that the distribution of paths from a pair of diplexers (e.g.,circuits 150, 152) do not necessarily need to be coupled to twocorresponding enable switches (e.g., S10, S11). For example, the outputpaths from the first diplexer are shown to be coupled to the first andsecond enable switches S10, S11 through their respective switches S4,S5; and the output paths from the second diplexer are shown to becoupled to the second enable switch S11 and the third enable switch S12(instead of the first enable switch S10) through their respectiveswitches S6, S7. Similarly, the output paths from the third diplexer areshown to be coupled to the third enable switch S12 and the first enableswitch S10 through their respective switches S8, S9.

FIG. 11 shows that in some embodiments, a distributed network of signalpaths 100 between two common nodes 102 does not necessarily need to haveall of the paths configured as described herein in reference to FIGS.5-8 and 10. In the example of FIG. 11, paths associated with Circuit 1,Circuit 2 and Circuit 3 are similar to the example of FIG. 10; pathsassociated with Circuit 4 and Circuit 5 are similar to the examples ofFIGS. 5-8; and paths associated with Circuit 6 are similar to theexamples of FIG. 3. Paths such as those associated with Circuit 6 can beimplemented in situations where, for example, band paths are notsensitive to isolation performance.

In the examples described herein in reference to FIGS. 5-11, variousdistributed networks of signal paths can be viewed as having threelayers of switches. For example, diplexer selection switches (e.g., S1and S2 in FIGS. 5-8) can be a layer, port selection switches (e.g.,S3-S6) can be a layer, and enable switches (e.g., S7 and S8) can be alayer. It will be understood that one or more features of the presentdisclosure can also be implemented in systems having different numbersof switch layers.

In some embodiments, switches in such different layers can havedifferent isolation properties. Accordingly, such differences inisolation properties can be utilized when distributing the signal pathsto yield desired isolation performance for some or all of the signalpaths.

In some embodiments, switches within a given layer can have differentisolation properties, or alternatively, different diplexer channels canhave different isolation properties. Accordingly, such differences inisolation properties can be utilized when distributing the signal pathsto yield desired isolation performance for some or all of the signalpaths.

In various examples herein, distributed network of signal paths aredescribed in the context of diplexers. However, it will be understoodthat one or more features of the present disclosure can be implementedwith other signal conditioning circuits, including, for example,multiplexers. Also, the diplexer examples are described in the contextof a single common node being an input, and the two diplexed nodes beingthe outputs. However, it will be understood that diplexers can beoperated in reverse, such that the distributed paths are on the outputside.

FIG. 12 shows a process 200 that can be implemented to fabricate adevice such as a module having one or more features as described herein.In block 202, a plurality of multiplexers can be mounted or provided ona substrate such as a packaging substrate. Such multiplexers caninclude, for example, diplexers. Each multiplexer can be configured tomultiplex a plurality of ports onto a common port.

In block 204, a plurality of multiplexer-selection switches can bemounted or provided to allow selectable routing of RF signals betweenthe common ports of the multiplexers and an input node. In block 206, aplurality of port-selection switches can be mounted or provided to allowselectable routing of RF signals to and/or from the plurality of portsof each multiplexer. In block 208, a plurality of enable switches can bemounted or provided to allow selectable routing of RF signals betweenone or more selected port-selection switches and an output node. Inblock 210, electrical connections can be formed such that a path betweenthe input node and the output node through a port of a correspondingmultiplexer includes at least two open switches when the path is notenabled.

In some embodiments, one or more features of the present disclosure canbe implemented in a number of products. For example, FIG. 13 shows ablock diagram of an RF module 300 (e.g., a front-end module) having apackaging substrate 302 such as a laminate substrate. Such a module caninclude one or more LNAs; and in some embodiments, such LNA(s) can beimplemented on a semiconductor die 304. An LNA implemented on such a diecan be configured to receive RF signals through selected signal paths asdescribed herein. Such an LNA can also benefit from the one or moreadvantageous features associated with improved isolation associated withdisabled signal paths.

The module 300 can further include a plurality of switches implementedon one or more semiconductor die 306. Such switches can be configured toprovide the various switching functionalities as described herein,including providing improved isolation by having an increased number ofopen switches in selected disabled signal paths.

The module 300 can further include a plurality of diplexers and/orfilters (collectively indicated as 310) configured to process RFsignals. Such diplexers/filters can be implemented as surface-mountdevices (SMDs), as part of an integrated circuit (IC), of somecombination thereof. Such diplexers/filters can include or be based on,for example, SAW filters, and can be configured as high Q devices.

In FIG. 13, a distributed network of signal paths is collectivelyindicated as 308. Such a network of signal paths can include one or morefeatures as described herein to provide, among others, improvedisolation between an antenna port (not shown) and an LNA port. In someembodiments, some or all of the network of signal paths can beimplemented as or be facilitated by conductor traces on or within thepackaging substrate, conductor features on or within semiconductor die,wirebonds, or any combination thereof.

In some implementations, an architecture, device and/or circuit havingone or more features described herein can be included in an RF devicesuch as a wireless device. Such an architecture, device and/or circuitcan be implemented directly in the wireless device, in one or moremodular forms as described herein, or in some combination thereof. Insome embodiments, such a wireless device can include, for example, acellular phone, a smart-phone, a hand-held wireless device with orwithout phone functionality, a wireless tablet, a wireless router, awireless access point, a wireless base station, etc. Although describedin the context of wireless devices, it will be understood that one ormore features of the present disclosure can also be implemented in otherRF systems such as base stations.

FIG. 14 schematically depicts an example wireless device 400 having oneor more advantageous features described herein. In some embodiments,such advantageous features can be implemented in a front-end (FE) module300. In some embodiments, such a FEM can include more or less componentsthan as indicated by the dashed box.

PAs in a PA module 412 can receive their respective RF signals from atransceiver 410 that can be configured and operated to generate RFsignals to be amplified and transmitted, and to process receivedsignals. The transceiver 410 is shown to interact with a basebandsub-system 408 that is configured to provide conversion between dataand/or voice signals suitable for a user and RF signals suitable for thetransceiver 410. The transceiver 410 is also shown to be connected to apower management component 406 that is configured to manage power forthe operation of the wireless device 400. Such power management can alsocontrol operations of the baseband sub-system 408 and other componentsof the wireless device 400.

The baseband sub-system 408 is shown to be connected to a user interface402 to facilitate various input and output of voice and/or data providedto and received from the user. The baseband sub-system 408 can also beconnected to a memory 404 that is configured to store data and/orinstructions to facilitate the operation of the wireless device, and/orto provide storage of information for the user.

In the example wireless device 400, the front-end module 300 can includea distributed network of signal paths (100) configured to provide one ormore functionalities as described herein. Such a network of signal pathscan be in communication with an antenna switch module (ASM) 414. In someembodiments, at least some of the signals received through an antenna420 can be routed from the ASM 414 to one or more low-noise amplifiers(LNAs) 418 through the distributed network of signal paths (100).Amplified signals from the LNAs 418 are shown to be routed to thetransceiver 410.

A number of other wireless device configurations can utilize one or morefeatures described herein. For example, a wireless device does not needto be a multi-band device. In another example, a wireless device caninclude additional antennas such as diversity antenna, and additionalconnectivity features such as Wi-Fi, Bluetooth, and GPS.

Examples Related to Diversity Receive (DRx) Implementation:

Using one or more main antennas and one or more diversity antennas in awireless device can improve quality of signal reception. For example, adiversity antenna can provide additional sampling of RF signals in thevicinity of the wireless device. Additionally, a wireless device'stransceiver can be configured to process the signals received by themain and diversity antennas to obtain a receive signal of higher energyand/or improved fidelity, when compared to a configuration using onlythe main antenna.

To reduce the correlation between signals received by the main anddiversity antennas and/or to enhance antenna isolation, the main anddiversity antennas can be separated by a relatively large physicaldistance in the wireless device. For example, the diversity antenna canbe positioned near the top of the wireless device and the main antennacan be positioned near the bottom of the wireless device, or vice-versa.

The wireless device can transmit or receive signals using the mainantenna by routing corresponding signals from or to the transceiverthrough an antenna switch module. To meet or exceed designspecifications, the transceiver, the antenna switch module, and/or themain antenna can be in relatively close physical proximity to oneanother in the wireless device. Configuring the wireless device in thismanner can provide relatively small signal loss, low noise, and/or highisolation.

In the foregoing example, the main antenna being physically close to theantenna switch module can result in the diversity antenna beingpositioned relatively far from the antenna switch module. In such aconfiguration, a relatively long signal path between the diversityantenna and the antenna switch module can result in significant lossand/or addition of loss associated with the signal received through thediversity antenna. Accordingly, processing of the signal receivedthrough the diversity antenna, including implementation of one or morefeatures as described herein, in the close proximity to the diversityantenna can be advantageous.

FIG. 15 shows that in some embodiments, one or more features of thepresent disclosure can be implemented in a diversity receive (DRx)module 300. Such a module can include a packaging substrate 302 (e.g., alaminate substrate) configured to receive a plurality of components, aswell to provide or facilitate electrical connections associated withsuch components.

In the example of FIG. 15, the DRx module 300 can be configured toreceive an RF signal from a diversity antenna (not shown in FIG. 15) atan input 320 and route such an RF signal to a low-noise amplifier (LNA)332. It will be understood that such routing of the RF signal caninvolve carrier-aggregation (CA) and/or non-CA configurations. It willalso be understood that although one LNA (e.g., a broadband LNA) isshown, there may be more than one LNAs in the DRx module 300. Dependingon the type of LNA and the mode of operation (e.g., CA or non-CA), anoutput 334 of the LNA 332 can include one or more frequency componentsassociated with one or more frequency bands.

In some embodiments, some or all of the foregoing routing of the RFsignal between the input 320 and the LNA 332 can be facilitated by anassembly of one or more switches 322 between the input 320 and anassembly of diplexer(s) and/or filter(s) (collectively indicated as324), and an assembly of one or more switches 330 between thediplexer/filter assembly 324 and the LNA 332. In some embodiments, theswitch assemblies 322, 330 can be implemented on, for example, one ormore silicon-on-insulator (SOI) die. In some embodiments, some or all ofthe foregoing routing of the RF signal between the input 320 and the LNA332 can be achieved without some or all of the switches associated withthe switch-assemblies 322, 330.

In the example of FIG. 15, the diplexer/filter assembly 324 is depictedas including two example diplexers 326 and two individual filters 328.It will be understood that the DRx module 300 can have more or lessnumbers of diplexers, and more or less numbers of individual filters.Such diplexer(s)/filter(s) can be implemented as, for example,surface-mount devices (SMDs), as part of an integrated circuit (IC), ofsome combination thereof. Such diplexers/filters can include or be basedon, for example, SAW filters, and can be configured as high Q devices.

In some embodiments, the DRx module 300 can include a control componentsuch as a MIPI RFFE interface 340 configured to provide and/orfacilitate control functionalities associated with some or all of theswitch assemblies 322, 330 and the LNA 332. Such a control interface canbe configured to operate with one or more I/O signals 342.

FIG. 16 shows that in some embodiments, a DRx module 300 having one ormore features as described herein (e.g., DRx module 300 of FIG. 15) canbe included in an RF device such as a wireless device 500. In such awireless device, components such as user interface 502, memory 504,power management 506, baseband sub-system 508, transceiver 510, poweramplifier (PA) 512, antenna switch module (ASM) 514, and antenna 520 canbe generally similar to the examples of FIG. 14.

In some embodiments, the DRx module 300 can be implemented between oneor more diversity antennas and the ASM 514. Such a configuration canallow an RF signal received through the diversity antenna 530 to beprocessed (in some embodiments, including amplification by an LNA) withlittle or no loss of and/or little or no addition of noise to the RFsignal from the diversity antenna 530. Such processed signal from theDRx module 300 can then be routed to the ASM through one or more signalpaths 532 which can be relatively lossy.

In the example of FIG. 16, the RF signal from the DRx module 300 can berouted through the ASM 514 to the transceiver 510 through one or morereceive (Rx) paths. Some or all of such Rx paths can include theirrespective LNA(s). In some embodiments, the RF signal from the DRxmodule 300 may or may not be further amplified with such LNA(s).

One or more features of the present disclosure can be implemented withvarious cellular frequency bands as described herein. Examples of suchbands are listed in Table 4. It will be understood that at least some ofthe bands can be divided into sub-bands. It will also be understood thatone or more features of the present disclosure can be implemented withfrequency ranges that do not have designations such as the examples ofTable 4.

TABLE 4 Tx Frequency Range Rx Frequency Range Band Mode (MHz) (MHz) B1FDD 1,920-1,980 2,110-2,170 B2 FDD 1,850-1,910 1,930-1,990 B3 FDD1,710-1,785 1,805-1,880 B4 FDD 1,710-1,755 2,110-2,155 B5 FDD 824-849869-894 B6 FDD 830-840 875-885 B7 FDD 2,500-2,570 2,620-2,690 B8 FDD880-915 925-960 B9 FDD 1,749.9-1,784.9 1,844.9-1,879.9 B10 FDD1,710-1,770 2,110-2,170 B11 FDD 1,427.9-1,447.9 1,475.9-1,495.9 B12 FDD699-716 729-746 B13 FDD 777-787 746-756 B14 FDD 788-798 758-768 B15 FDD1,900-1,920 2,600-2,620 B16 FDD 2,010-2,025 2,585-2,600 B17 FDD 704-716734-746 B18 FDD 815-830 860-875 B19 FDD 830-845 875-890 B20 FDD 832-862791-821 B21 FDD 1,447.9-1,462.9 1,495.9-1,510.9 B22 FDD 3,410-3,4903,510-3,590 B23 FDD 2,000-2,020 2,180-2,200 B24 FDD 1,626.5-1,660.51,525-1,559 B25 FDD 1,850-1,915 1,930-1,995 B26 FDD 814-849 859-894 B27FDD 807-824 852-869 B28 FDD 703-748 758-803 B29 FDD N/A 716-728 B30 FDD2,305-2,315 2,350-2,360 B31 FDD 452.5-457.5 462.5-467.5 B33 TDD1,900-1,920 1,900-1,920 B34 TDD 2,010-2,025 2,010-2,025 B35 TDD1,850-1,910 1,850-1,910 B36 TDD 1,930-1,990 1,930-1,990 B37 TDD1,910-1,930 1,910-1,930 B38 TDD 2,570-2,620 2,570-2,620 B39 TDD1,880-1,920 1,880-1,920 B40 TDD 2,300-2,400 2,300-2,400 B41 TDD2,496-2,690 2,496-2,690 B42 TDD 3,400-3,600 3,400-3,600 B43 TDD3,600-3,800 3,600-3,800 B44 TDD 703-803 703-803

For the purpose of description, it will be understood that“multiplexer,” “multiplexing” and the like can include “diplexer,”“diplexing” and the like.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Wherethe context permits, words in the above Detailed Description using thesingular or plural number may also include the plural or singular numberrespectively. The word “or” in reference to a list of two or more items,that word covers all of the following interpretations of the word: anyof the items in the list, all of the items in the list, and anycombination of the items in the list.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

While some embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

1. A carrier aggregation circuit comprising: a common input node and a common output node; a multiplexer configured to support first and second bands; a first path implemented between the common input node and the common output node, and configured to support the first band, the first path including a pre-multiplexer switch, the multiplexer, a first post-multiplexer switch, and a first enable switch; and a second path implemented between the common input node and the common output node, and configured to support the second band, the second path including the pre-multiplexer switch, the multiplexer, a second post-multiplexer switch, and a second enable switch different than the first enable switch.
 2. The carrier aggregation circuit of claim 1 wherein the common input node is an antenna node and the multiplexer is configured to support a plurality of receive bands.
 3. The carrier aggregation circuit of claim 2 wherein the common output node is configured to be coupled to an input of a low-noise amplifier.
 4. The carrier aggregation circuit of claim 1 wherein the multiplexer is configured as a diplexer.
 5. The carrier aggregation circuit of claim 1 wherein the first and second paths are configured to support a carrier aggregation operation involving the first and second bands when in a carrier aggregation mode.
 6. The carrier aggregation circuit of claim 5 wherein each of the first and second paths is enabled to couple the common input node to the common output node.
 7. The carrier aggregation circuit of claim 6 wherein the first path is configured such that each of the pre-multiplexer switch, the first post-multiplexer switch and the first enable switch is closed, and the second path is configured such that each of the pre-multiplexer switch, the second post-multiplexer switch and the second enable switch is closed.
 8. The carrier aggregation circuit of claim 1 wherein the first and second paths are configured to support a non-carrier aggregation operation involving either of the first and second bands when in a non-carrier aggregation mode.
 9. The carrier aggregation circuit of claim 8 wherein one of the first and second paths is enabled to couple the common input node to the common output node, and the other of the first and second paths is disabled to isolate the common output node from the common input node.
 10. The carrier aggregation circuit of claim 9 wherein the first path is enabled such that each of the pre-multiplexer switch, the first post-multiplexer switch and the first enable switch is closed, and the second path is disabled such that the pre-multiplexer switch is closed and each of the second post-multiplexer switch and the second enable switch is open to provide the isolation of the common output node from the common input node.
 11. The carrier aggregation circuit of claim 9 wherein the second path is enabled such that each of the pre-multiplexer switch, the second post-multiplexer switch and the second enable switch is closed, and the first path is disabled such that the pre-multiplexer switch is closed and each of the first post-multiplexer switch and the first enable switch is open to provide the isolation of the common output node from the common input node.
 12. The carrier aggregation circuit of claim 9 wherein the isolation of the common output node from the common input node for the disabled one of the first and second paths is achieved by more than one switch being open along the disabled path.
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 25. A radio-frequency module comprising: a packaging substrate configured to receive and support a plurality of components; and a carrier aggregation circuit implemented relative to the packaging substrate, and including a common input node and a common output node, and a multiplexer configured to support first and second bands, the carrier aggregation circuit further including a first path implemented between the common input node and the common output node, and configured to support the first band, the first path including a pre-multiplexer switch, the multiplexer, a first post-multiplexer switch, and a first enable switch, the carrier aggregation circuit further including a second path implemented between the common input node and the common output node, and configured to support the second band, the second path including the pre-multiplexer switch, the multiplexer, a second post-multiplexer switch, and a second enable switch different than the first enable switch.
 26. The radio-frequency module of claim 25 wherein the common input node is an antenna node and the multiplexer is configured to support a plurality of receive bands.
 27. The radio-frequency module of claim 26 wherein the antenna node is configured to be coupled to a diversity antenna.
 28. The radio-frequency module of claim 26 further comprising a low-noise amplifier having an input coupled to the common output node of the carrier aggregation circuit.
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 34. A carrier aggregation circuit comprising: a common input node and a common output node; a first filter configured to support a first band, and a second filter configured to support a second band; a first path implemented between the common input node and the common output node, and configured to support the first band, the first path including the first filter, a first post-filter switch, and a first enable switch; and a second path implemented between the common input node and the common output node, and configured to support the second band, the second path including the second filter, a second post-filter switch, and a second enable switch different than the first enable switch.
 35. The carrier aggregation circuit of claim 34 wherein the first filter and the second filter are implemented as a multiplexer.
 36. The carrier aggregation circuit of claim 35 wherein the multiplexer is configured as a diplexer.
 37. The carrier aggregation circuit of claim 35 wherein each of the first and second paths further includes a pre-multiplexer switch implemented between the common input node and the multiplexer, such that the pre-multiplexer switch is shared by the first and second paths.
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